Post-War Urban Damage Mapping Using InSAR: The Case of Mosul City in Iraq

Ali Darvishi Boloorani,Mehdi Darvishi,Qihao Weng,Xiangtong Liu

doi:10.3390/ijgi10030140

Abstract

Urban infrastructures have become imperative to human life. Any damage to these infrastructures as a result of detrimental activities would accrue huge economical costs and severe casualties. War in particular is a major anthropogenic calamity with immense collateral effects on the social and economic fabric of human nations. Therefore, damaged buildings assessment plays a prominent role in post-war resettlement and reconstruction of urban infrastructures. The data-analysis process of this assessment is essential to any post-disaster program and can be carried out via different formats. Synthetic Aperture Radar (SAR) data and Interferometric SAR (InSAR) techniques help us to establish a reliable and fast monitoring system for detecting post-war damages in urban areas. Along this thread, the present study aims to investigate the feasibility and mode of implementation of Sentinel-1 SAR data and InSAR techniques to estimate post-war damage in war-affected areas as opposed to using commercial high-resolution optical images. The study is presented in the form of a survey to identify urban areas damaged or destroyed by war (Islamic State of Iraq and the Levant, ISIL, or ISIS occupation) in the city of Mosul, Iraq, using Sentinel-1 (S1) data over the 2014–2017 period. Small BAseline Subset (SBAS), Persistent Scatterer Interferometry (PSI) and coherent-intensity-based analysis were also used to identify war-damaged buildings. Accuracy assessments for the proposed SAR-based mapping approach were conducted by comparing the destruction map to the available post-war destruction map of United Nations Institute for Training and Research (UNITAR); previously developed using optical very high-resolution images, drone imagery, and field visits. As the findings suggest, 40% of the entire city, the western sectors, especially the Old City, were affected most by ISIS war. The findings are also indicative of the efficiency of incorporating Sentinel-1 SAR data and InSAR technique to map post-war urban damages in Mosul. The proposed method could be widely used as a tool in damage assessment procedures in any post-war reconstruction programs.

Highlights

Urban environments are complex systems that support human life and must constantly be monitored in order to avoid catastrophic loss of infrastructures and lives [1]
Results from the Small BAseline Subset (SBAS)-Persistent Scatterer Interferometry (PSI) displacement and coherence-based change detection maps agree with the United Nations Institute for Training and Research (UNITAR) map, in terms of identified damaged regions, especially in the old city
This study presented an analysis of post-war-affected areas of Mosul City using S1 data

Summary

Introduction

Urban environments are complex systems that support human life and must constantly be monitored in order to avoid catastrophic loss of infrastructures and lives [1]. An accurate, reliable, cost-effective, and fast post-war mapping-monitoring system would facilitate the process of assessing damages inflicted by war on urban infrastructures. New generations of satellite sensors have been launched and several automated techniques have been developed for the study of urban areas, exploiting both active synthetic aperture radar (SAR) and passive sensors [2,3] Many of these studies address the issue of change detection in urban areas, incorporating SAR images with different approaches such as using multi-pass interferometric data in 3D reconstruction and monitoring buildings, those affected by systematic displacements related to natural hazards, landslides [4]. Using SAR and VHR (Very High Resolution) optical images to quantify damages caused by the 2003 Bam earthquake in Iran [5] and using multi-SAR data to study the 2009 L’Aquila earthquake in Italy [6]

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Results

Discussion

Conclusion